Acceptance and wide spread use of the CO2 laser in endoscopic surgery awaits a safe, reliable, inexpensive fiber optic system to permit flexible delivery of thermalizing anergy colinear with visualization of the event. Because of the need for this device in medicine and also because its fabrication is suitable for a small high technology firm, commercialization is very promising. Based on both the findings of research to date and on the likelyhood of a successful program, the proposed approach is to investigate silver halide (AgH) for fiber optic fabrication. AgH has a unique combination of desirable properties. It is nontoxic, flexibile, workable at relatively low temperatures, non-hygroscopic and has a high theoretical infrared transmissivity. This application of AgH is new and a number of novel techniques to lower impurity-related transmission losses have yet to be attempted. The proposal details experience and expertise in the ultrapurification, crystalline microstructuring and vapor deposition of all AgH materials. The proposed objectives are (1) a significant reduction of fiber transmission losses coupled with (2) the introduction of innovative fiber optic fabrication methods for control of crystalline fine structure and purification enhancement.